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在超声速压气机气动设计时,为实现设计点高性能和宽喘振裕度,提出采用优化方法以设计点性能为目标进行叶片设计,通过转/静子叶片几何手动修改提高压气机喘振裕度。以NASA Rotor 37为原型,应用此方法进行更高性能超声速压气机转子气动设计,并匹配静子,构成压气机级。结果表明:超声速压气机转子通道激波推出和静子大攻角分离是失速发生的主要原因,因此分别进行转子叶片前掠设计、改变叶尖稠度,以控制激波位置,单转子喘振裕度可从约7%提高到18%以上;静子上采用前掠、切向弯、修改叶片数及几何进口角等措施,最终将此压气机级的喘振裕度由约18%提高到30%以上。 相似文献
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用扰流插板使涡扇发动机进气道内产生不对称分布的总压畸变并使发动机出现喘振。在进气道出口即发动机进口截面测取两种不同转速下发动机的喘振压力波。应用小波分析奇异点理论,采用模极大值原理和高阶Daubechies小波多尺度分析,对喘振压力信号进行处理,得到发动机喘振波在其进口截面的波形分布特征。揭示了在两种转速下,喘振波在截面上的分布相似,其频率和幅值与转速成正比。截面中心部分表现为正脉冲,周围部分为负脉冲。在垂直方向上的幅值较大,而两翼较小。对该分布特征进行了分析,初步的推论为:高压压气机引起喘振,稳态压力畸变最严重的区域和未受到畸变扰动的区域,喘振波最为强烈。 相似文献
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分析了轴对称子午流面上力的平衡关系及其流线曲率、气体绕压气机轴线旋转产生的惯性离心力和叶片力三个影响因素,并研究了流动分离的机理和如何对流动分离进行抑制的思路,在此基础上提出了叶片气动正交的准则。采用气动正交准则对某风扇的第一排静子叶片进行了改型设计,获得了气动正交后的新叶片,并对其进行了全三维粘性流场计算,计算结果表明采用气动正交叶片的流场结构明显好于原型叶片。从全三维特性计算结果看,采用气动正交的叶片其喘振裕度也要明显好于原型叶片。 相似文献
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《中国航空学报》2020,33(8):2099-2109
Bent inlet pipes are often used in centrifugal compressors due to limited installation space, and an understanding of the effect on compressor stability is essential for safety and durability. This paper firstly investigates flow instability behaviors in two compressors, one with a straight inlet pipe and the other with an S-shaped bent pipe. In detail, it analyzes the resulting flow fields, instability evolution paths and surge boundaries. The results show that the S-shaped pipe obviously affects the flow field at high mass flow rates, while reverse flow mainly influences the flow field at low mass flow rates. Reverse flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent pipe. In addition, centrifugal compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large size. Since the S-shaped pipe is not dominant in the creation and extension of reverse flow, it does not exacerbate the stability of the central compressor to a great extent. Last but not least, the S-shaped pipe is noted to delay the occurrence of surge at 90% rotating speed, which suggests the possibility of improving compressor stability with bent inlet pipes. This result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of centrifugal compressors. 相似文献
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本文对现役燃气涡转发动机发生的重大喘振故障作了分析,并提出防喘监控系统方案.依此方案研制出的FCJ-124防喘监控系统,在发动机试车台上和实际飞机发动机上进行多次监控喘振试验,取得了较满意的效果. 相似文献
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